1. Department of Obstetrics and Gynecology, Aalborg University Hospital, Aalborg, Denmark.
2. Center for Clinical Research, North Denmark Regional Hospital, Hjoerring, Denmark.
3. Center for Sensory-Motor Interaction, Department of Health Science and Technology, The Faculty of Medicine, Aalborg University, Aalborg, Denmark.
4. Department of Clinical Medicine, Aalborg University Hospital, Aalborg University, Aalborg, Denmark.